A substrate guided relay may be utilized in a head-up display (HUD) system or the like to generate one or more copies of an input light and to homogenize the input light applied to the user's eye. Such a substrate guided relay generally may comprise an input coupler, a slab guide, and an output coupler. The input coupler is disposed at an angle with respect to the slab guide to internally reflect the input beam and to make multiple copies of the input beam by application of Brewster's formula to control the internal reflection of the copies of the input beam. However, alignment of the input coupler and the slab guide may be difficult. The surface bond of the input coupler on the slab guide controls alignment in a first direction since one surface of the input coupler abuts the surface of the slab guide, but alignment of the input coupler to the edges of the slab guide involves precision to achieve a sufficient amount of alignment.
It will be appreciated that for simplicity and/or clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements may be exaggerated relative to other elements for clarity. Further, if considered appropriate, reference numerals have been repeated among the figures to indicate corresponding and/or analogous elements.